It is somewhat accepted that obesity may be a risk factor for asthma that affects asthma severity and quality of life (QOL). The trial described below contradicts that assumption.
This one-year study from San Antonio, Texas examined the relationship between body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]) and asthma severity, spirometry findings, health care utilization (HCU), and QOL.
The trial enrolled almost 1,000 patients (evenly split between children and adults), representing an underserved population.
In children, 45% were overweight/obese. In adults, 58% were obese.
There was no relationship in children between BMI and severity of asthma, spirometry findings, QOL, or HCU.
In adults, there was no relationship between BMI and asthma severity or HCU. Higher BMI was associated with a significant reduction in QOL. BMI had an inverse relationship with forced vital capacity but with no other spirometric values.
Obesity was not associated with worse asthma severity, spirometry findings, QOL, or HCU in children. In adults with asthma, obesity was associated with lower forced vital capacity and QOL but not with severity or HCU.
Impact of obesity in asthma: evidence from a large prospective disease management study. Peters JI, McKinney JM, Smith B, Wood P, Forkner E, Galbreath AD. Ann Allergy Asthma Immunol. 2011 Jan;106(1):30-5.
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